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New thread to debate V-4000
- Thread starter nosepc
- Start date
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You do know that your dominator is nothing more than a j-pole with skirt??
You do know that being stubborn gets you nowhere.
Suit yourself.
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You do know that your dominator is nothing more than a j-pole with skirt??
Of course I know that but what you don't know is it takes a pair of parallel elements to cause cancellation to happen when the currents are equal and opposite. We have 5 elements at the cone including the vertical inside. Of which, NONE are parallel or equal in current.
EZNEC uses the NEC based engine to drive the program. CST uses the MOM engine. I see no way to adapt EZNEC to function like CST. The programming would be vastly different and is why CST cost thousands.
My Sirio Vector 4000 is still in it's box unassembled until I move to the mountains. I've done my research on it way before I ever bought it. It won out over the Gain Master simply because I want an aluminum antenna. I have the A99 up for the time being. Plus I've been wanting to get an A99(my first one)with the ground plane kit to see for myself what all the fuss is about and also to have the best tuned A99 there is. Right now I can talk to another base station operator who has an A99 twenty feet off the ground twenty-five miles away in a medium noise city environment. Not bad at all considering that I'm only using 4 watts but with awesome modulation.
Hopefully the day will come where I'll be talking on my Vector and not just that but actually have an antenna farm of my own.
Moooooo!
Because I'm not an expert at modeling I cannot tell you 100% certain that there is no way for EZNEC to model this antenna. What I can tell you is there is no evidence to support anyone has ever built a model of the Vector in EZNEC that was even close to accurate. They all contain major errors with respect to radiation currents along with phase and gain.
The only reason I hold a glimmer of hope is because L. B. Cebik who was very much an expert didn't use the word impossible when describing the chances of anyone making an accurate model in EZNEC. He used the word "difficult". That is why I sometimes intentionally antagonize people who claim they have an accurate model, to prove it by seeing if it can pass the phase test in adaptation with adding another collinear section.
People who will not accept the wrong results with the knowledge to spot the difference, along with a big budget, purchase CST when they need to model complicated designs similar to this. If anyone is up to the challenge of a "difficult" EZNEC build, I'm able to tell within minuets if it's close to accurate by adding 4 wires to any existing model.
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4000
tx wavrider,
I did find some 1/8" dacron rope, it looks better the paracord. tx,
debate, I'll say. its been going on quite a while, reading some of the older
posts. Why is the 4000 in question, why would sirio or FM antenna companies make antennas that don't work? I don't get it. that picture model of the FM
antenna and the basket maybe confuses. but shockwave I'm sure
it works. all my antenna models went by way of a disk crash a few years
ago so back to paper and pencil. I sketched out a 3/4 wave wire vertical,
current, starting from zero at the tip. a phase reversal at 1/2 wave. then
drew in some 1/4 sleeve wires on each side, and the phase reversal
with them. transmission line mode inside, antenna mode outside now in
phase. a low gain collinear. the sketch looks like 1/2 of a 3 element
collinear in the old ham books which netted gain over a dipole. the q section,
or basket, providing the phase reversal for the 4000. the article I posted
had a nice 2 mtr version (if it got read). albeit fed different
73 dean
tx wavrider,
I did find some 1/8" dacron rope, it looks better the paracord. tx,
debate, I'll say. its been going on quite a while, reading some of the older
posts. Why is the 4000 in question, why would sirio or FM antenna companies make antennas that don't work? I don't get it. that picture model of the FM
antenna and the basket maybe confuses. but shockwave I'm sure
it works. all my antenna models went by way of a disk crash a few years
ago so back to paper and pencil. I sketched out a 3/4 wave wire vertical,
current, starting from zero at the tip. a phase reversal at 1/2 wave. then
drew in some 1/4 sleeve wires on each side, and the phase reversal
with them. transmission line mode inside, antenna mode outside now in
phase. a low gain collinear. the sketch looks like 1/2 of a 3 element
collinear in the old ham books which netted gain over a dipole. the q section,
or basket, providing the phase reversal for the 4000. the article I posted
had a nice 2 mtr version (if it got read). albeit fed different
73 dean
Henry, thank you for pointing out my minor error as accuracy is important to me. I knew there was a vast difference in the algorithms used between NEC and CST although, I was off a little. EZNEC does use the MoM engine that is best at modeling wire antennas. CST is another animal altogether that allows you to choose between 6 different engines to suit various applications.
I don't think anybody is claiming the S4/Vector doesn't work or work well, there has developed two schools of thought on how it might work.
I can't say for sure, but I think I agree with your view of the situation as you briefly described, but I can't get my Eznec model to show even close to the 4.15 dbi in free space as reported out by Sirio.
So the discussion has taken on the issues with Eznec's limitations vs. CST modeling and it gets pretty heated at times. This thread is only the tip of the iceberg.
Welcome to the forum dean.
You've also noticed the more time you spend in EZNEC making the model more similar to the antenna, the closer it gets to the unity gain 1/2 wave EZNEC mistakenly views it as. Previously, others could argue that was because the Sigma was just a fancy looking 1/2 wave J-pole. That all flies right out the window when you CAN'T use a 180 degree phase shift in the field to drive a second collinear element because it cancels the constructive cone radiation.
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